JP7171396B2 - Developer carrier, process cartridge and electrophotographic image forming apparatus - Google Patents

Description

The present invention relates to a developer carrier used in an electrophotographic image forming apparatus, a process cartridge having the developer carrier, and an electrophotographic image forming apparatus.

In electrophotographic image forming apparatuses (copiers, facsimiles, printers, etc. using electrophotographic methods), an electrophotographic photosensitive member (hereinafter also referred to as a "photosensitive member") is first charged by a charging roller and then exposed. Thus, an electrostatic latent image is formed on the photoreceptor. Further, the developer in the developer container is applied onto the developer carrying member by the developer regulating member, and is conveyed to the developing area by the developer carrying member. The developer conveyed to the development area develops the electrostatic latent image on the photoreceptor in the gap between or in the vicinity of the photoreceptor and the developer carrier. After that, the developer on the photoreceptor is transferred to the recording paper by the transfer means and fixed by heat and pressure. The developer remaining on the photoreceptor is removed by a cleaning blade.

Since the developer carrier is often used in contact with the photoreceptor, it is desired that the surface layer of the developer carrier has a low hardness in order to reduce rotational torque. In addition, resins having functional groups tend to absorb moisture, and when resins having functional groups are used for the surface layer of the developer carrier, there is a risk that the dimensional variation of the developer carrier due to moisture absorption will reduce printing accuracy. was there. Therefore, in order to reduce the hardness of the surface layer and suppress dimensional fluctuation due to moisture absorption, a developer carrier having a surface layer made of a urethane resin using an olefin-based polyol has been proposed (Patent Documents 1 and 2). .

JP-A-2001-106762 JP 2006-301512 A

In recent years, a developer with a small particle size has been used to improve image quality. However, the small particle size developer is less likely to be charged than the large particle size developer.
In a developer carrier having a surface layer made of a urethane resin using an olefin polyol, as described in Patent Documents 1 and 2, the small-diameter developer is not uniformly triboelectrically charged, resulting in a non-static charge. A phenomenon (hereinafter referred to as fogging) occurs in which the developer adheres to the electrostatic latent image portion.

One aspect of the present invention is directed to providing a developer carrier capable of suppressing fogging and stably forming high-quality electrophotographic images.
Another aspect of the present invention is directed to providing an electrophotographic image forming apparatus capable of stably outputting high-quality electrophotographic images and a process cartridge used therein.

According to one aspect of the present invention, there is provided a developer carrier having a substrate and a surface layer, the surface layer containing a urethane resin, the urethane resin having a tertiary amine structure, has a portion having an aliphatic hydrocarbon structure between two urethane bonds, and the aliphatic hydrocarbon structure has a distance corresponding to a straight chain with 10 or more carbon atoms between the two urethane bonds, Provided is a developer carrier having a straight chain portion with 10 or more carbon atoms.

According to another aspect of the present invention, there is provided a process cartridge detachably attached to a main body of an electrophotographic image forming apparatus, comprising: a developer container containing a developer; and a developer for conveying the developer. and a carrier, wherein the developer carrier is the developer carrier described above.

Further, according to another aspect of the present invention, an electrophotographic photoreceptor, a charging member disposed so as to be able to charge the electrophotographic photoreceptor, and a developer carrier for supplying a developer to the electrophotographic photoreceptor are provided. The electrophotographic image forming apparatus is provided, wherein the developer carrier is the developer carrier described above.

According to one aspect of the present invention, it is possible to obtain a developer carrier capable of suppressing fogging and stably forming high-quality electrophotographic images.
Further, according to another aspect of the present invention, it is possible to obtain a process cartridge that contributes to stable formation of high-quality electrophotographic images. Furthermore, according to another aspect of the present invention, it is possible to obtain an electrophotographic image forming apparatus capable of stably forming high-quality electrophotographic images.

1 is a conceptual diagram showing an example of a developer carrier according to one aspect of the present invention; FIG. FIG. 5 is a schematic configuration diagram showing a process cartridge according to another aspect of the invention; FIG. 2 is a schematic configuration diagram showing an electrophotographic image forming apparatus according to another aspect of the present invention; 1 is a schematic configuration diagram showing an example of a non-contact developing type developing device; FIG.

When the developer passes between the developer carrier and the developer regulating member, the developer rolls on the developer carrier, thereby uniformly charging the developer. If the developer with a small particle diameter is present together with the developer with a large particle diameter, it is difficult for the developer to come into contact with the developer carrying member and the developer regulation member, and it is difficult for the developer to roll. Therefore, it becomes difficult to charge the small-particle developer from the developing member, and the small-particle developer has a small amount of charge.

A developer with a small particle size and a small amount of charge easily adheres to the surface of the photoreceptor, causing fogging. When the charge amount distribution of the developer becomes broad, the adhesion of developer with a small charge amount to the non-electrostatic latent image area is suppressed by changing the bias setting between the photoreceptor and the developer carrier. is difficult and can result in fogging.

Accordingly, the present inventors conducted repeated studies with the aim of suppressing fogging by obtaining a developer carrier that makes it easier for the developer to roll on the developer carrier and that can equalize the charge amount of the developer. .
As a result, it has a tertiary amine structure and a portion having an aliphatic hydrocarbon structure between two urethane bonds, and the aliphatic hydrocarbon structure has 10 carbon atoms between the two urethane bonds. A developer carrying member having a surface layer containing a urethane resin having a straight chain portion having 10 or more carbon atoms for providing a distance corresponding to the above straight chain is effective for achieving the above object. Found it.

The reason why such a developer carrying member can well achieve the above object is not necessarily bound by the following theory, but is presumed as follows.

A nitrogen atom having a lone pair of electrons is present in the tertiary amine structure, and since this nitrogen atom serves as a hydrogen bonding point, it forms a hard segment together with the partial structure of the urethane bond. At this time, the hard segment forms a large domain in the present invention as compared with the case where the urethane resin does not have a tertiary amine structure and consists only of urethane bonds. In addition, due to the properties of the tertiary amine contained in the hard segment, it is possible to charge the developer from the nitrogen atom having a lone pair of electrons.

On the other hand, when the urethane resin has a portion having an aliphatic hydrocarbon chain sandwiched between two urethane bonds, the aliphatic hydrocarbon chain does not contain a polar atom and therefore constitutes a soft segment of the urethane resin. The soft segment has a size that correlates with the number of carbon atoms in the linear portion of the aliphatic hydrocarbon chain. Here, in the aliphatic hydrocarbon chain, when a straight chain portion having 10 or more carbon atoms is introduced to provide a distance corresponding to a straight chain having 10 or more carbon atoms between the two urethane bonds, soft Segments can also form domains of relatively large size.

As a result, hard segments derived from urethane bonds, hard segments derived from tertiary amine structures, and soft segments derived from straight-chain moieties having 10 or more carbon atoms are present on the outer surface of the developer carrier. It will happen. The developer in contact with such an outer surface has good rolling properties on the outer surface, and the presence of the tertiary amine structure allows the developer to be well charged. As a result, the charge amount distribution of the developer becomes sharp, and it is considered that the occurrence of fogging on the electrophotographic image can be suppressed.

Modes for carrying out the present invention will be described in more detail below.
FIG. 1 shows a cross-sectional view of a roller-shaped developer carrier according to one aspect of the present invention in a direction perpendicular to the axial direction. In the developer carrier 1 shown in FIG. 1A, a surface layer 3 is formed directly on the outer peripheral surface of a cylindrical or hollow cylindrical substrate 2 .
Further, the developer carrier 1 may have one or more elastic layers 4 formed between the substrate 2 and the surface layer 3, as shown in FIG. 1(b). Furthermore, as shown in FIG. 1(c), the developer carrier 1 has a three-layer structure in which an intermediate layer 5 is arranged between the surface layer 3 and the elastic layer 4, or a multi-layer structure in which many intermediate layers 5 are arranged. It may be a configuration. As the intermediate layer, a known intermediate layer for developer carrier can be used.

<Substrate>
The substrate functions as an electrode and support member for the developer carrier and is, for example, a metal or alloy such as aluminum, copper alloys, stainless steel; iron plated with chromium or nickel; synthetic materials having electrical conductivity. It is made of a conductive material such as resin. The substrate may be solid or hollow.

<Surface layer>
The surface layer is a resin layer containing a urethane resin, the urethane resin has a tertiary amine structure in the molecule, and has a portion having an aliphatic hydrocarbon structure between two urethane bonds; The group hydrocarbon structure has a straight chain portion of 10 or more carbon atoms to provide a distance between the two urethane bonds corresponding to a straight chain of 10 or more carbon atoms.

［構造式（１）中、
Ｒ１１は炭素数２以上４以下の直鎖状または分岐鎖状のアルキレン基を表し、
ｎは０以上４以下の整数であり、ｎが２以上４以下の場合、複数のＲ１１は互いに同じであっても異なっていてもよく、
ｎが０の場合、記号「＊１」、「＊２」および「＊３」は、各々独立に、炭素数１以上４以下の直鎖状または分岐鎖状のアルキル基との結合部、または、前記ウレタン樹脂のポリマー鎖との結合部を表し、
ｎが１の場合、記号「＊１」、「＊２」、「＊３」、および、「＊４」は、前記ウレタン樹脂のポリマー鎖との結合部であり、
ｎが２以上４以下の場合、記号「＊１」、「＊２」、「＊３」および「＊４」は、各々独立に、水素原子との結合部、ヒドロキシ基を有してもよい炭素数１以上４以下の直鎖状または分岐鎖状のアルキル基との結合部、または、前記ウレタン樹脂のポリマー鎖との結合部を表し、ｎが２以上４以下の場合における複数の「＊４」は互いに同じであっても異なっていてもよく、また、ｎが２以上４以下の場合においては、記号「＊１」、「＊２」、「＊３」、および、複数の「＊４」から選ばれる少なくとも４つは、前記ウレタン樹脂のポリマー鎖との結合部である。］ The urethane resin according to the present invention preferably has a partial structure represented by structural formula (1). That is, the tertiary amine structure of the urethane resin according to the present invention is preferably derived from the partial structure represented by structural formula (1).

[in the structural formula (1),
R11 represents a linear or branched alkylene group having 2 to 4 carbon atoms,
n is an integer of 0 or more and 4 or less, and when n is 2 or more and 4 or less, the plurality of R11 may be the same or different,
When n is 0, the symbols "*1", "*2" and "*3" are each independently a bond with a linear or branched alkyl group having 1 to 4 carbon atoms, or , represents the bonding portion with the polymer chain of the urethane resin,
When n is 1, the symbols "*1", "*2", "*3", and "*4" are bonding portions with the polymer chain of the urethane resin,
When n is 2 or more and 4 or less, the symbols "*1", "*2", "*3" and "*4" may each independently have a bond with a hydrogen atom or a hydroxy group. Represents a bonding portion with a linear or branched alkyl group having 1 to 4 carbon atoms, or a bonding portion with the polymer chain of the urethane resin, and when n is 2 or more and 4 or less, multiple "* 4" may be the same or different, and when n is 2 or more and 4 or less, the symbols "*1", "*2", "*3", and multiple "* At least four selected from 4” are bonding portions with the polymer chain of the urethane resin. ]

The urethane resin contains a portion having a specific aliphatic hydrocarbon structure between two adjacent urethane bonds. The specific aliphatic hydrocarbon structure has 10 or more carbon atoms, preferably 50 or more carbon atoms, in order to provide a distance corresponding to a straight chain of 10 or more carbon atoms between the two adjacent urethane bonds has a linear portion of By having such a portion, the size of the soft segment can be increased, and together with the presence of the hard segment derived from the tertiary amine structure, the rolling property of the developer on the outer surface of the developer carrier can be improved. It can be improved further. As a result, the charge amount of the developer can be made more uniform, that is, the charge amount distribution of the developer can be made sharper.

More preferably, the linear portion has 100 or more and 1,500 or less carbon atoms. This is because the soft segment and hard segment form a more appropriate domain size in the urethane resin. When the number of carbon atoms in the straight chain portion is 100 or more, rolling of the developer is further promoted. In addition, since the number of carbon atoms in the linear portion is 1500 or less, the proportion of soft segments present in the surface layer does not become too high, and the hardness of the surface layer does not decrease. As a result, it is possible to prevent the developer from adhering to the surface of the developer carrier and causing the charge amount to become too large.

［構造式（２）中、Ｌ１は、脂肪族炭化水素構造を表し、Ｒ２１は一方のウレタン結合とＬ１とを連結する連結鎖を表し、Ｒ２３は他方のウレタン結合とＬ１とを連結する連結鎖を表し、ｐおよびｒは各々独立して０または１であり、「※１」は一方のウレタン結合との結合部を表し、「※２」は、他方のウレタン結合との結合部を表し、Ｌ１は、下記構造式（３）で示される構造を含む：

構造式（３）中、ｑは、２５以上７５０以下の整数を表し、Ｒ３３は、水素原子または炭素数１以上４以下のアルキル基を表し、複数のＲ３３は互いに同じであっても異なっていてもよく、「※３」は、Ｒ２１または一方のウレタン結合との結合部を表し、「※４」は、Ｒ２３または他方のウレタン結合との結合部を表す。］
ここで、構造式（３）中、ｑは脂肪族炭化水素の直鎖の炭素数を１／２にした値と同義であり、本発明の効果を発現するにあたって、ｑは２５以上の整数が好ましく、より好ましくは５０以上７５０以下の整数である。 Further, the concentration of nitrogen atoms in the tertiary amine structure is preferably 0.1% by mass or more and 4.0% by mass or less based on the mass of the urethane resin. As a result, a negative charge is more properly imparted to the developer. It is preferable that the linking portion of two adjacent urethane bonds has a structure represented by the following structural formula (2).

[In Structural Formula (2), L1 represents an aliphatic hydrocarbon structure, R21 represents a linking chain linking one urethane bond and L1, and R23 represents a linking chain linking the other urethane bond and L1. represents, p and r are each independently 0 or 1, "* 1" represents the bonding portion with one urethane bond, "* 2" represents the bonding portion with the other urethane bond, L1 comprises a structure represented by structural formula (3) below:

In structural formula (3), q represents an integer of 25 or more and 750 or less, R33 represents a hydrogen atom or an alkyl group having 1 or more and 4 or less carbon atoms, and a plurality of R33 may be the same or different. Alternatively, "*3" represents R21 or the bonding portion with one urethane bond, and "*4" represents R23 or the bonding portion with the other urethane bond. ]
Here, in the structural formula (3), q is synonymous with a value obtained by halving the number of carbon atoms in the straight chain of the aliphatic hydrocarbon, and q is an integer of 25 or more in order to achieve the effects of the present invention. It is preferably an integer of 50 or more and 750 or less.

In addition, the linear portion of the aliphatic hydrocarbon structure may have an unsaturated bond.
A method of introducing the above aliphatic hydrocarbon structure between two adjacent urethane bonds includes reaction of polyisocyanate with olefinic polyol.

(Olefin polyol)
Examples of olefinic polyols include the following.
Polybutadiene polyol, polyisoprene polyol, polyethylene polyol, polypropylene polyol. Polybutadiene polyol and polyisoprene polyol may have unsaturated bonds or may be modified into saturated bonds by a hydrogenation reaction or the like.

(polyisocyanate)
As the polyisocyanate, polyisocyanates known for synthesis of urethane resins or polyisocyanates that can be used for synthesis of urethane resins can be used.
Examples of polyisocyanates include aliphatic polyisocyanates such as ethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), cycloaliphatic polyisocyanates such as isophorone diisocyanate (IPDI), cyclohexane 1,3-diisocyanate, cyclohexane 1,4-diisocyanate. aromatic isocyanates such as formula polyisocyanates, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate (MDI), polymeric diphenylmethane diisocyanate, xylylene diisocyanate, naphthalene diisocyanate and Isocyanate compounds such as copolymers thereof, isocyanurates, TMP adducts, biurets, blocks thereof and the like can be mentioned. At least one of these can be used.

［構造式（４）中、
Ｒ４５は炭素数２以上４以下の直鎖状または分岐鎖状のアルキレン基を表し、ｓは０以上４以下の整数であり、ｓが２以上４以下の場合、複数のＲ４５は互いに同じであっても異なっていてもよい。
Ｒ４１、Ｒ４２、Ｒ４３およびＲ４４は、各々独立に、下記（ａ）、（ｂ）、（ｃ）および（ｄ）から選ばれるいずれかであり、ｓが２以上４以下の場合において、複数のＲ４４は互いに同じであっても異なっていてもよく、但し、ｓ＝１の場合、Ｒ４１、Ｒ４２、Ｒ４３およびＲ４４の全てが、下記（ｂ）、（ｃ）および（ｄ）から選ばれるいずれかであり、ｓ＝２以上４以下の場合、Ｒ４１、Ｒ４２およびＲ４３および２以上４以下の個数のＲ４４のうちの少なくとも４つが、下記（ｂ）、（ｃ）および（ｄ）から選ばれるいずれかである：
（ａ）水素原子、または炭素数１乃至４の直鎖状または分岐鎖状のアルキル基；
（ｂ）炭素数１以上８以下の直鎖状または分岐鎖状のヒドロキシアルキル基；
（ｃ）炭素数２以上８以下の直鎖状または分岐鎖状のアミノアルキル基；
（ｄ）下記構造式（５）で示される基：

構造式（５）中、ｔは２または３である。複数のＲ５１はそれぞれ独立して炭素数２以上５以下の直鎖状または分岐鎖状のアルキレン基を表す。］。 (amino alcohol)
The tertiary amine structure of the polyurethane resin can be introduced by reacting an aminoalcohol containing a tertiary amine structure with polyisocyanate. A compound represented by the following structural formula (4) is particularly preferable as the aminoalcohol containing a tertiary amine structure.

[in the structural formula (4),
R45 represents a linear or branched alkylene group having 2 to 4 carbon atoms, s is an integer of 0 to 4, and when s is 2 to 4, multiple R45 are the same. may be different.
R41, R42, R43 and R44 are each independently selected from the following (a), (b), (c) and (d), and when s is 2 or more and 4 or less, a plurality of R44 may be the same or different, provided that when s=1, all of R41, R42, R43 and R44 are any one selected from (b), (c) and (d) below. Yes, when s = 2 or more and 4 or less, at least four of R41, R42 and R43 and the number of R44 of 2 or more and 4 or less are any selected from the following (b), (c) and (d) be:
(a) a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms;
(b) a linear or branched hydroxyalkyl group having 1 to 8 carbon atoms;
(c) a linear or branched aminoalkyl group having 2 to 8 carbon atoms;
(d) a group represented by the following structural formula (5):

In structural formula (5), t is 2 or 3. A plurality of R51 each independently represents a linear or branched alkylene group having 2 or more and 5 or less carbon atoms. ].

Examples of (a) include hydrogen atom, methyl group, ethyl group, propyl group and butyl group.

Examples of (b) include hydroxymethyl, hydroxyethyl, hydroxypropyl, hydroxybutyl, hydroxypentyl, hydroxyhexyl, hydroxyheptyl, hydroxyoctyl and 2-hydroxypropyl groups.

Examples of (c) include aminoethyl group, aminopropyl group, aminobutyl group, aminopentyl group, aminohexyl group, aminoheptyl group and aminooctyl group.

Examples of R51 include an ethylene group, a propylene group, a butylene group, a pentylene group and a 2-methylbutylene group.

(polyol)
The material for forming the surface layer may contain a polyol having no olefin structure in addition to each of the above materials. A polyol has a plurality of hydroxyl groups in its molecule, and the hydroxyl groups react with the polyisocyanate. Polyols having no olefin structure are not particularly limited, and include, for example, polyether polyols and polyester polyols. Polyether polyols include polyethylene glycol, polypropylene glycol and polytetramethylene glycol.

Polyester polyols having no olefin structure include diol components such as 1,4-butanediol, 3-methyl-1,4-pentanediol and neopentyl glycol, triol components such as trimethylolpropane, Polyester polyols obtained by condensation reaction with dicarboxylic acids or carboxylic acid anhydrides such as adipic acid, phthalic anhydride, terephthalic acid and hexahydroxyphthalic acid can be mentioned. The polyether polyol and polyester polyol may be prepolymers chain-extended with an isocyanate such as 2,4-tolylene diisocyanate (TDI), 1,4 diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), if necessary. .

The ratio (L/M) of the number (L) of isocyanate groups to the number (M) of hydroxyl groups and amino groups in the urethane resin is preferably 1.0 or more and 2.0 or less. The number of hydroxyl groups and amino groups is the total number of hydroxyl groups in the polyol and hydroxyl groups and amino groups in the aminoalcohol.

In the surface layer, if necessary, general resins other than the polyurethane resin according to the present invention, rubber materials, compounding agents, conductivity imparting agents, non-conductive fillers, A cross-linking agent and a catalyst may be added.

The resin to be added is not particularly limited. mentioned.

Examples of rubber materials include ethylene-propylene-diene copolymer rubber, acrylonitrile-butadiene rubber, chloroprene rubber, natural rubber, isoprene rubber, styrene-butadiene rubber, silicone rubber, epichlorohydrin rubber, and urethane rubber.

Compounding agents include fillers, softeners, processing aids, tackifiers, antitackifiers, foaming agents and the like that are generally used for resins.

Conductive metals such as aluminum and copper; fine particles of conductive metal oxides such as conductive zinc oxide, conductive tin oxide and conductive titanium oxide; An ion-conducting agent such as fluoromethylsulfate can be used.

Non-conductive fillers include silica, quartz powder, titanium oxide, or calcium carbonate.

Examples of cross-linking agents include, but are not limited to, tetraethoxysilane, di-t-butylperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane or dicumyl. A peroxide is mentioned.

If the surface layer of the developer carrier requires a surface roughness, fine particles may be added to the surface layer to control the roughness. It is preferable that the fine particles for roughness control have a volume average particle size of 3 μm or more and 20 μm or less, since a developer carrying member having an excellent ability to convey the developer can be obtained. Moreover, the amount of the fine particles added to the surface layer is preferably 1 part or more and 50 parts or less per 100 parts by mass of the resin solid content of the surface layer so as not to impair the effects of the present invention. Fine particles of polyurethane resin, polyester resin, polyether resin, polyamide resin, acrylic resin, and phenol resin can be used as fine particles for roughness control.

The method for forming the surface layer is not particularly limited, but examples thereof include spraying, dipping, and roll coating with a coating liquid. The dip coating method in which the coating liquid overflows from the upper end of the dip bath is preferable as a method for forming the surface layer because it is simple and excellent in production stability.

A developer carrier according to an aspect of the present invention includes a non-contact type developing device and a contact type developing device using a magnetic one-component developer or a non-magnetic one-component developer, and a developing device using a two-component developer. can be applied to any of

<Elastic layer>
The elastic layer provides elasticity to the developer carrier for forming a nip of a predetermined width at the contact portion between the developer carrier and the photoreceptor. Therefore, one or more layers may be arranged between the substrate and the surface layer.

As a constituent material of the elastic layer, a material known as an elastic layer or a material that can be used as an elastic layer can be used. It is preferable that the elastic layer is generally formed of a molding of a rubber material. Examples of rubber materials include the following.
Ethylene-propylene-diene copolymer rubber (EPDM), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR), fluororubber, Silicone rubber, epichlorohydrin rubber, hydrogenated NBR, urethane rubber.
These can be used alone or in combination of two or more.

Among these, silicone rubber is particularly preferred because it does not easily cause compression set in the elastic layer even when other members (such as a developer regulating blade) come into contact with it for a long period of time. Examples of silicone rubbers include cured products of addition-curing silicone rubbers. Furthermore, it is particularly preferable to use a cured product of addition-curable dimethyl silicone rubber.

Various additives such as conductivity-imparting agents, non-conductive fillers, cross-linking agents and catalysts are appropriately blended in the elastic layer.

Carbon black; conductive metals such as aluminum and copper; fine particles of conductive metal oxides such as zinc oxide, tin oxide and titanium oxide can be used as the conductivity-imparting agent. At least one of these can be used. Of these, carbon black is particularly preferred because it is relatively easily available and provides good electrical conductivity. When carbon black is used as the conductivity imparting agent, it is preferably blended in an amount of 2 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the rubber material in the material for forming the elastic layer.

Non-conductive fillers include silica, quartz powder, titanium oxide, zinc oxide or calcium carbonate. At least one of these can be used.

Cross-linking agents include di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane or dicumyl peroxide. At least one of these can be used.

<Process cartridge, electrophotographic image forming apparatus>
A process cartridge according to another aspect of the present invention is detachably attached to a main body of an electrophotographic image forming apparatus, and includes a developer container containing a developer and a developer carrier for conveying the developer. , the developer carrier is the developer carrier according to one aspect of the present invention.

An electrophotographic image forming apparatus according to another aspect of the present invention comprises an electrophotographic photoreceptor, a charging member arranged to charge the electrophotographic photoreceptor, and a developer supplying a developer to the electrophotographic photoreceptor. It has a developer carrier, and the developer carrier is the developer carrier according to one aspect of the present invention.

A process cartridge and an electrophotographic image forming apparatus according to another aspect of the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto.

FIG. 2 is a schematic configuration diagram showing an example of a process cartridge using the developer carrier according to one aspect of the present invention as a developing member. FIG. 3 is a schematic configuration diagram showing an example of an electrophotographic image forming apparatus in which the process cartridge is detachably incorporated.

The process cartridge shown in FIG. 2 has a developer container 9, a developer carrier 7, a developer regulating member 17, and a developer supply member 8, and is detachable from the main body of the electrophotographic image forming apparatus. have. In FIG. 3, a photosensitive member 18, which is an image carrier on which an electrostatic latent image is formed, is rotated in the direction of arrow R1. By rotating in the direction of arrow R2, the developer carrier 7 conveys the developer to the developing area where the developer carrier 7 and the photoreceptor 18 face each other. A developer supply member 8 is in contact with the developer carrier, rotates in the R3 direction, and supplies the developer to the surface of the developer carrier 7 .

A charging roller 6 as a charging member, a transfer member (transfer roller) 10, a cleaner container 11, a cleaning blade 12, a fixing device 13, a pickup roller 14, and the like are provided around the photosensitive member 18 so as to be charged. there is The photoreceptor 18 is charged by the charging roller 6 . Then, exposure is performed by irradiating the photoreceptor 18 with laser light from the laser generator 16 to form an electrostatic latent image corresponding to the desired image. The electrostatic latent image on the photoreceptor 18 is developed with a developer in a developer container 9 of a process cartridge as a developer to obtain an image. For the development, so-called reversal development is performed in which the exposed portion is developed with the developer. A transfer material (paper) P is conveyed into the apparatus from a paper supply unit 15 by a pickup roller 14 or the like. is transferred onto the transfer material (paper) P by . The transfer material (paper) P on which the image is placed is conveyed to the fixing device 13, and the developer is fixed on the transfer material (paper) P. As shown in FIG. Further, the developer left on the photosensitive member 18 is scraped off by the cleaning blade 12 and stored in the cleaner container 11 .

It is preferable that the thickness of the developer layer on the developer carrier is regulated by the developer regulating member 17 coming into contact with the developer carrier 7 via the developer. A regulating blade is generally used as the developer regulating member that comes into contact with the developer carrying member, and can be suitably used in the present invention as well.

As the material constituting the regulating blade, rubber elastic bodies such as silicone rubber, urethane rubber, and NBR; synthetic resin elastic bodies such as polyethylene terephthalate; and metal elastic bodies such as phosphor bronze plates and stainless steel (SUS) plates can be used. , or a composite thereof. Furthermore, for the purpose of controlling the chargeability of the developer, the structure may be such that a charge control material such as resin, rubber, metal oxide or metal is attached to an elastic support such as rubber, synthetic resin or metal elastic body. can also In this case, the regulating blade is used so that the portion of the charge control material comes into contact with the developer carrier. As such a regulating blade, a metal elastic body bonded with resin or rubber is particularly preferable. As these resins or rubbers, urethane rubbers, urethane resins, polyamide resins, and nylon resins, which are easily charged positively, are preferred.

FIG. 4 is a schematic configuration diagram showing an example of a non-contact developing type developing device having a developer carrier according to an aspect of the present invention. In FIG. 4, an electrostatic latent image holding member for holding an electrostatic latent image, such as a photosensitive member 18, rotates in the arrow B direction. The developer carrier 1 carries and conveys a one-component developer, which is a magnetic developer, supplied from a container (developer container 9) for containing the developer. By rotating the developer carrier 1 in the direction of the arrow A, the developer is conveyed to the developing region C where the developer carrier 1 and the photoreceptor 18 face each other. As shown in FIG. 4, a magnet is inscribed in the hollow cylindrical base 2 of the developer carrier 1 to magnetically attract and hold the developer on the developer carrier 1. As shown in FIG. A magnet roller 19 is arranged.

A stirring blade 20 for stirring the developer is provided in the developer container 9 . In the example of FIG. 4, a developer regulating member 17 is used to regulate the layer thickness of the developer conveyed to the development area C. As shown in FIG. In this developing device, a thin developer layer is formed on the developer carrier 1 by elastically pressing the developer regulating member 17 against the developer carrier 1 through the developer layer. The thickness of the thin layer of developer formed on the developer carrier 1 is preferably thinner than the minimum gap between the developer carrier 1 and the photoreceptor 18 in the development zone C.

A development bias voltage is applied to the developer carrier 1 by a development bias power supply 21 as bias means in order to cause the one-component developer containing the magnetic developer carried on the developer carrier 1 to fly. .

The developing device can be used as a process cartridge detachably attached to the main body of the electrophotographic image forming apparatus, or can be used by being directly incorporated in the main body of the electrophotographic image forming apparatus.

Specific examples and comparative examples according to the present invention are shown below. The invention is not limited to these examples.

<Synthesis of isocyanate group-terminated prepolymer>
An example of synthesizing an isocyanate group-terminated prepolymer, which is one of the raw materials for synthesizing the urethane resin for the surface layer, is shown below.

(Preparation of raw material polyol)
Raw material polyols B-1 to B-10 were prepared. Commercial products shown in Table 1 were used for B-4 and B-5. B-1 to B-3 and B-6 to B-10 were synthesized by the method shown below.

(Synthesis of raw material polyol B-6)
200 g of isopropanol and 80 g of hydrogen peroxide (concentration: 60%) were charged into a 1 L stainless steel autoclave, and the inside of the autoclave was vacuum degassed while cooling. After adding 200 g (3.7 mol) of 1,3-butadiene, the reaction was carried out at 125° C. under 20 atmospheric pressure for 4 hours.
After the reaction was completed, the reaction mixture was cooled, unreacted 1,3-butadiene was removed, 1 L of distilled water was added, and the resulting polymer was separated after washing with shaking using a separating funnel. Further, purification was performed using a rotary evaporator at 75° C. or higher and 80° C. or lower at 15 mmHg for 4 hours.
Subsequently, 10 parts of 1% Pd alumina spheres (manufactured by N E Chemcat) were filled as a hydrogenation catalyst in a stainless mesh basket fixed in an autoclave equipped with a stirrer. Further, a reaction solution prepared by dissolving 10 parts of the produced polymer in 90 parts of cyclohexane was introduced into the autoclave, and hydrogenation reaction was carried out at 160° C. for 3 hours under a hydrogen atmosphere of 15 atm. After completion of the hydrogenation reaction, purification was performed using a rotary evaporator at 75° C. or higher and 80° C. or lower at 15 mmHg for 4 hours to obtain raw material polyol B-6.

(Synthesis of raw material polyols B-1 to B-3 and B-7 to B-10)
B-1 was synthesized by subjecting commercial product B-4 to the same hydrogenation reaction as described above. Similarly, B-2 was synthesized by subjecting the commercial product B-5 to the same hydrogenation reaction as described above.
Synthesis of B-3 was carried out as follows. A three-necked flask equipped with a stirrer and a thermometer was charged with 50.0 g (0.015 mol) of B-1 as a diol in THF solvent, and 4.0 g of sodium hydride (60%: fluid Paraffin solvent) was added dropwise and stirred for 30 minutes. After the reaction vessel was cooled to 0° C., 2.0 g (0.032 mol) of 2-iodoethanol (manufactured by Tokyo Kasei Kogyo Co., Ltd.) was added dropwise and stirred for 1 hour. Then, 1 L of distilled water was added, and after washing with shaking using a separating funnel, the produced polymer was separated. Further, the raw material polyol B-3 was synthesized by purifying at 75° C. to 80° C. and 15 mmHg for 4 hours using a rotary evaporator.

Other starting polyols B-7 to B-10 were synthesized in the same manner as in the synthesis of starting polyol B-6, except that the starting materials used in the reaction and the mixing amounts were changed as shown in Table 2 below. .

Furthermore, commercially available polyol compounds shown in Table 3 below were prepared.

(Measurement of molecular weight of raw material polyol)
The apparatus and conditions used for measuring the number average molecular weight (Mn) in the examples are as follows.
Measuring instrument: HLC-8120GPC (manufactured by Tosoh Corporation)
Column: TSKgel SuperHZMM (manufactured by Tosoh Corporation) x 2 Solvent: THF
Temperature: 40°C
Flow rate of THF: 0.6 ml/min
A 0.1% by mass THF solution was used as a measurement sample. Furthermore, the measurement was performed using an RI (refractive index) detector as a detector.
As a standard sample for creating a calibration curve, TSK standard polystyrene A-1000, A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40, F- 80 and F-128 (manufactured by Tosoh Corporation) were used to prepare a calibration curve. Based on this, the number average molecular weight was determined from the retention time of the measurement sample obtained.

Table 4 below shows the structure, the number of repeating structures, the number of straight-chain carbon atoms, and the hydroxyl value contained in the starting polyols obtained by synthesis or commercially available products.

(Synthesis of isocyanate group-terminated prepolymer A-1)
Under a nitrogen atmosphere, 8.8 parts by mass of isocyanate C-1 (pure-MDI, trade name: Millionate MT manufactured by Tosoh Corporation) is added to methyl ethyl ketone (hereinafter referred to as MEK) in a reaction vessel so that the final solid content is 50%. Dissolved. Thereafter, while maintaining the temperature in the reaction vessel at 65° C., 100.0 parts by mass of raw material polyol B-1 was gradually added dropwise to the reaction vessel.
After completion of the dropwise addition, the mixture was reacted at a temperature of 65° C. for 2 hours. The resulting reaction mixture was cooled to room temperature to obtain an isocyanate group-terminated prepolymer A-1 having a solid content of 50% and an isocyanate group content of 1.4% by weight.

(Synthesis of isocyanate group-terminated prepolymers A-2 to A-12)
The raw material polyol used for the synthesis, the type and mixing amount of isocyanate, and the reaction time were changed as shown in Table 5. Otherwise, isocyanate group-terminated prepolymers A-2 to A-12 were obtained as solutions having a solid content of 50% in the same manner as in the synthesis of isocyanate group-terminated prepolymer A-1.
As isocyanates other than C-1, C-2 (polymeric MDI, trade name: Millionate MR, manufactured by Tosoh Corporation) and C-3 (tolylene diisocyanate, trade name: Cosmonate T80, manufactured by Mitsui Chemicals, Inc.) were used.

<Synthesis of amino alcohol>
(Synthesis of amino alcohol D-11)
50.0 g (0.27 mol) of tetraethylenepentamine (manufactured by Tokyo Chemical Industry Co., Ltd.) is reacted with 97.6 g (0.66 mol) of phthalic anhydride (manufactured by JFE Chemical Co., Ltd.) in chloroform, and the primary amine is phthalimide. A group-protected compound was obtained. After that, 150.3 g (1.06 mol) of iodomethane (manufactured by Tokyo Chemical Industry Co., Ltd.) was added in acetonitrile and refluxed for 4 hours. The resulting compound was dissolved in 500 ml of ethanol, 30.0 g (0.60 mol) of hydrazine hydrate (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the mixture was refluxed for 5 hours to remove the compound from which the phthalimide group was eliminated. Obtained. Next, the solvent was distilled off under reduced pressure, the resulting compound was dissolved in 300 ml of ethanol, 79.4 g (2.65 mol) of paraformaldehyde was added, and the mixture was boiled and refluxed for 6 hours. The solvent was distilled off under reduced pressure, and after liquid separation, extraction and drying, amino alcohol D-11 represented by the following structural formula (6) was obtained.

(Synthesis of amino alcohol D-1)
10.0 g (0.11 mol) of 1,4-diaminobutane as a raw material amine and 200 ml of pure water as a reaction solvent are stirred in a reaction vessel equipped with a stirrer, a thermometer, a dropping device and a temperature control device. was warmed to 40°C. Next, 58.0 g (1.00 mol) of propylene oxide as an additional raw material was gradually added dropwise over 30 minutes while maintaining the reaction temperature at 40° C. or lower. Further, the mixture was stirred for 2 hours and reacted to obtain a reaction mixture. The resulting reaction mixture was heated under reduced pressure to distill off water to obtain amino alcohol D-1 (tetrakis(2-hydroxypropyl)butylene diamine).

(Synthesis of amino alcohols D-2 to D-10)
Amino alcohols D-2 to D-10 were synthesized in the same manner as for amino alcohol D-1, except that the starting amino alcohols and the types and amounts of additional raw materials were changed as shown in Table 6.

The structures of the obtained amino alcohols D-1 to D-10 are shown in Structural Formula (7) and Table 7.

(Preparation of amino alcohols D'-1 to D'-6, D'-9, D'-10)
As amino alcohols D'-1 to D'-6, D'-9 and D'-10, commercial products having structures shown in structural formula (8) and Table 8 below were used.

(Production of elastic roller K-1)
A ground aluminum cylindrical tube having an outer diameter of 10 mm and an arithmetic mean roughness Ra of 0.2 μm was coated with a primer (trade name, DY35-051; manufactured by Dow Corning Toray Co., Ltd.) and baked to obtain a substrate. This substrate was placed in a mold, and an addition-type silicone rubber composition mixed with the materials shown below was injected into the cavity formed in the mold.
・Liquid silicone rubber material (trade name SE6724A/B; manufactured by Dow Corning Toray Co., Ltd.) 100 parts by mass ・Carbon black (trade name Toka Black #4300; manufactured by Tokai Carbon Co., Ltd.) 15 parts by mass ・Silica powder (as a heat resistance imparting agent ) 0.2 parts by mass and platinum catalyst 0.1 parts by mass Subsequently, the mold was heated to vulcanize and cure the silicone rubber at a temperature of 150°C for 15 minutes. After the substrate with the cured silicone rubber layer formed on its peripheral surface was removed from the mold, the substrate was further heated at 180° C. for 1 hour to complete the curing reaction of the silicone rubber layer. In this manner, an elastic roller K-1 was produced in which a silicone rubber elastic layer having a thickness of 0.7 mm and a diameter of 11.4 mm was formed on the outer circumference of the substrate.

(Example 1)
A method of manufacturing the developer carrier according to Example 1 will be described below.
As materials for the surface layer forming coating liquid, the following materials were stirred and mixed.
・Isocyanate group-terminated prepolymer A-1: 98.3 parts by mass ・Amino alcohol D-1: 1.7 parts by mass ・Carbon black (trade name MA-230, manufactured by Mitsubishi Chemical Corporation): 10.0 parts by mass ・Urethane Resin fine particles (trade name, Artpearl C-400; manufactured by Negami Kogyo Co., Ltd.): 30.0 parts by mass Number of isocyanate groups in isocyanate group-terminated prepolymer A-1/Number of hydroxyl groups and amino groups in amino alcohol D-1 ( Index) was adjusted to 1.2.
Next, methyl ethyl ketone (MEK) was added so that the total solid content ratio was 30% by mass, and mixed with a sand mill. Then, the viscosity was adjusted to 10 to 13 cps with MEK to prepare a surface layer forming coating liquid.
The previously prepared elastic roller K-1 was immersed in the surface layer forming coating liquid to form a coating film of the coating liquid on the surface of the elastic layer of the elastic roller K-1, followed by drying. Further, a heat treatment was performed at a temperature of 160° C. for 1 hour to form a surface layer having a film thickness of about 15 μm on the outer periphery of the elastic layer.

(Examples 2 to 33)
A surface layer-forming coating liquid was prepared in the same manner as in Example 1, except that the materials shown in Table 9-1 below were used as materials for the surface layer-forming coating liquid. In the preparation, the ratio of the number of isocyanate groups in the isocyanate group-terminated prepolymer molecule/the number of hydroxyl groups and amino groups in the amino alcohol or polyol molecule (Index) was 1.2.
Then, each coating liquid was applied to the elastic roller K-1, dried and heated in the same manner as in Example 1 to prepare developer carriers according to Examples 2 to 33. For Example 21, polyol D-16 (Kuraray Polyol P-5010) was also added.

(Example 34)
A surface layer-forming coating liquid was prepared in the same manner as in Example 1, except that the materials shown in Table 9-2 below were used as materials for the surface layer-forming coating liquid.
Next, a ground aluminum cylindrical tube having an outer diameter of 10 mm and an arithmetic mean roughness Ra of 0.2 μm was prepared. This substrate was immersed in the surface layer forming coating liquid to form a coating film of the coating liquid on the surface of the substrate, followed by drying. Further, a heat treatment was performed at a temperature of 160° C. for 1 hour to form a surface layer having a film thickness of about 15 μm on the outer periphery of the substrate, and a developer carrier according to Example 34 was produced.

(Examples 35-66)
A surface layer-forming coating liquid was prepared in the same manner as in Example 1, except that the materials shown in Table 9-2 below were used as materials for the surface layer-forming coating liquid. In the preparation, the ratio of the number of isocyanate groups in the isocyanate group-terminated prepolymer molecule/the number of hydroxyl groups and amino groups in the amino alcohol or polyol molecule (Index) was 1.2.
In the same manner as in Example 34, each coating liquid was applied to the substrate, dried and heated to prepare developer carriers according to Examples 35-66.

Regarding Example 6 in Table 9-1 and Example 39 in Table 9-2, R21 in structural formulas (2) and (3) is —CH ₂ CH ₂ O—, and R23 is —OCH ₂ CH ₂ —. showing.

(Comparative example 1)
The following materials were stirred and mixed as materials for the surface layer forming coating liquid.
- 1.2 parts by weight of polyol D-15
· 98.8 parts by mass of isocyanate group-terminated prepolymer A-1
・ Carbon black (trade name MA-230, manufactured by Mitsubishi Chemical Corporation) 10.0 parts by mass ・ Urethane resin fine particles (trade name, Artpearl C-400; manufactured by Negami Kogyo Co., Ltd.) 30.0 parts by mass Then, in Example 1 A coating liquid for forming a surface layer according to Comparative Example 1 was prepared in the same manner as the method for preparing the coating liquid for forming a surface layer. In the preparation, the ratio of the number of isocyanate groups in the isocyanate group-terminated prepolymer molecule/the number of hydroxyl groups in the polyol molecule (Index) was 1.2. This surface layer forming coating liquid was applied to the surface of the silicone rubber elastic layer of the elastic roller K-1 in the same manner as in Example 1 and dried to form a surface layer. made.

(Comparative Examples 2-5)
A surface layer-forming coating liquid was prepared in the same manner as in Comparative Example 1, except that the materials shown in Table 10 below were used as materials for the surface layer-forming coating liquid. In the preparation, the ratio of the number of isocyanate groups in the isocyanate group-terminated prepolymer molecule/the number of hydroxyl groups in the polyol molecule (Index) was 1.2. Then, each coating liquid was applied to an elastic roller, dried and heated in the same manner as in Comparative Example 1 to prepare developer carriers according to Comparative Examples 2-5.

(Comparative Examples 6 to 10)
A surface layer-forming coating liquid was prepared in the same manner as in Comparative Example 1, except that the materials shown in Table 10 below were used as materials for the surface layer-forming coating liquid. In the preparation, the ratio of the number of isocyanate groups in the isocyanate group-terminated prepolymer molecule/the number of hydroxyl groups in the polyol molecule (Index) was 1.2. Then, each coating liquid was applied to the substrate, dried and heated in the same manner as in Example 34 to prepare developer carriers according to Comparative Examples 6 to 10.

<Developer charge amount evaluation>
The developer carriers according to Examples 1 to 33 and Comparative Examples 1 to 5 were incorporated into a cyan cartridge of a laser beam printer (trade name: LBP7700C, manufactured by Canon Inc.) to prepare image output test cartridges. This cartridge for image output test was charged into the laser beam printer, and five solid white images were output at a speed of 10 sheets/min. Then, the operation of the printer was stopped in the middle of outputting one solid white image. The developer is sucked from the developer layer formed on the developer carrier using a suction nozzle having an opening of Φ5 mm, and the charge amount and developer mass of the sucked developer are measured to determine the developer charge. Amount (μC/g) was determined. The charge amount was measured using a digital electrometer (trade name: 8252, manufactured by ADC Corporation).
Evaluation results are shown in Tables 11-1 and 11-3.

In addition, the developer carriers according to Examples 34 to 66 and Comparative Examples 6 to 10 were incorporated into genuine cartridges of a laser beam printer (trade name: LaserJet P3015n, manufactured by Hewlett-Packard) to prepare image output test cartridges. Using this image output test cartridge, evaluation was performed in the same manner as above. Evaluation results are shown in Tables 11-2 and 11-3.

<Evaluation of electric charge distribution>
The following method was used to evaluate the charge amount distribution of the developer.
As a conventionally known method for measuring the charge distribution of a developer, there is a charge amount distribution measurement method by a laser Doppler charge measurement method (E-Spart method using an E-Spart Analyzer (manufactured by Hosokawa Micron Corporation)). be. Such a method is widely used to measure developer chargeability. The results of measurement by the E-Spart method are obtained by measuring the charge amount of the developer in a charged state in an air stream, so useful information can be obtained for grasping the state of development. In particular, it is effective as a method for evaluating fog caused by insufficient charging of the developer, which is a subject of the present invention.

The developer charge amount distribution is measured by blowing off the developer layer formed on the developer carrier with nitrogen gas and introducing it into the measuring section (measuring cell) of E-Spart Analyzer (manufactured by Hosokawa Micron Corporation) through the sampling hole. I did it in Further, the developer was used until 3000 pieces were counted. The ratio (%) of the number of low-charge amount developers in the total developer measured using an ESPART analyzer was calculated and used as the low-charge amount developer ratio. A low charge was defined as a developer with a charge less than 30% of the peak charge. The evaluation criteria for the ratio of the number of low-charge developers are as follows. The measurement results are shown in Tables 11-1 to 11-3.

<Fog Evaluation>
Further, the developer adhering to the photoreceptor was peeled off with a transparent tape (trade name: polyester tape No. 550, manufactured by Nichiban Co., Ltd.) and pasted on white paper (Business Multipurpose 4200; manufactured by XEROX). , a sample for evaluation was obtained. Then, the reflection density R1 of the evaluation sample was measured with a reflection densitometer (TC-6DS/A; manufactured by Tokyo Denshoku Co., Ltd.). At that time, a green filter was used as the filter. On the other hand, the reflection density R0 was similarly measured for a reference sample in which only the transparent tape was adhered to white paper. The amount of decrease in the reflectance of the evaluation sample "R0-R1" (%) with respect to the reference sample was taken as the fogging value (%). When the fogging value is less than 2.5%, the fogging cannot be visually recognized at all or at a level at which it can hardly be recognized. Further, when the amount is 2.5% or more and less than 5.0%, fogging can be visually recognized, but is generally within the allowable range. On the other hand, when the fog value is 5.0% or more, the fog is at a level at which the fog can be clearly recognized visually.
The measurement results are shown in Tables 11-1 to 11-3.

<SEM Observation of Surface Layer>
As a method for confirming that the urethane resin in the surface layer of the developer carrier according to Example 1 forms hard segments and that the hard segments and soft segments alternately exist, a scanning electron microscope (SEM: Ultra-Plus) was used. (manufactured by Carl Zeiss)) was used.
A sample for SEM observation was prepared by bar-coating an aluminum sheet with a coating liquid prepared by removing carbon black and urethane resin fine particles from materials for preparing the coating liquid for surface layer formation to a film thickness of 15 μm. A secondary electron image of the obtained sample was observed under measurement conditions of an acceleration voltage of 0.5 kV or more and 1.0 kV or less and a WD of 3.0 mm or more and 3.5 mm or less.
As a result, it was observed that hard segments of 50 nm or more and 100 nm or less were uniformly scattered on the surface.

Similarly, surface observation of resins obtained by removing carbon black and urethane resin fine particles from the surface layer materials of Examples 4, 7, 12, 17, 24, 34, 37, 40, 45, 50 and 57 and Comparative Examples 1 and 6 was carried out. The results are shown in Tables 11-1 to 11-3.

In Examples 1 to 66, since the urethane resin according to the present invention was used for the surface layer, large hard segments were formed, and hard segments/soft segments were alternately formed on the surface. As a result, the charging of the developer became uniform, the charge amount distribution of the developer was suppressed narrowly, and fogging was reduced.

In particular, Examples 1 to 23 and 34 to 56 used aminoalcohols containing 2 to 5 tertiary amines in the molecule, and the nitrogen content derived from the tertiary amine structure was large. Therefore, it is considered that not only the rolling property of the developer is good, but also the charge imparting property to the developer is enhanced, and the charge amount distribution is suppressed to be stable and narrow.

Examples 1 to 33 and Examples 34 to 66 differ in the presence or absence of an elastic layer between the substrate and the surface layer. Examples 34-66) are evaluated. Compared to the contact developing method, the charge amount of the developer is slightly lower in the non-contact developing method, but it is considered that the difference in the developing device used for the evaluation is also included, and good results were obtained in all cases.

In Examples 1, 4, 7, 12, 17, 24, 34, 37, 40, 45, 50 and 57, the size of hard segments in the urethane resin was observed by SEM. As a result, it was observed that hard segments of 50 nm or more and 100 nm or less were uniformly scattered on the surface.

Examples 24 to 33 and 57 to 66 are urethane resins made from amine compounds containing one tertiary amine in the molecule. The charge amount distribution was wider and the fog slightly increased compared to the case where amino alcohol containing 2 to 5 tertiary amines in the molecule was used as a starting material, but all of the results were good.

When the surfaces of Comparative Examples 1 and 6 were observed with an SEM, the size of the hard segments was not identifiable. Comparative Examples 1 to 10 do not contain tertiary amines other than urethane bonds in the resin. Therefore, it is considered that the hard segment does not have a size of 50 nm or more and the charge imparting property to the developer is low, resulting in insufficient charge amount of the developer. Therefore, it is considered that the width of the charge amount distribution was widened and the fog was deteriorated.

DESCRIPTION OF SYMBOLS 1, 7... Developer carrier 2... Substrate 3... Surface layer 4... Elastic layer 5... Intermediate layer 6... Charging roller 8... Developer supplying member 9... Developer container 10 Transfer member 11 Cleaner container 12 Cleaning blade 13 Fixing device 14 Pick-up roller 15 Paper supply unit 16 Laser generator 17. .Developer regulating member 18.Photoreceptor 19.Magnet roller 20.Agitation blade 21.Development bias power supply

Claims (8)

A developer carrier having a substrate and a surface layer,
The surface layer contains a urethane resin,
The urethane resin is
Having a tertiary amine structure, and
Having a portion having an aliphatic hydrocarbon structure between two urethane bonds,
A development characterized in that the aliphatic hydrocarbon structure has a straight chain portion with 10 or more carbon atoms to provide a distance corresponding to a straight chain with 10 or more carbon atoms between the two urethane bonds. agent carrier. The urethane resin is
2. The developer carrier according to claim 1, having a partial structure represented by the following structural formula (1):

[in the structural formula (1),
R11 represents a linear or branched alkylene group having 2 to 4 carbon atoms,
n is an integer of 0 or more and 4 or less, and when n is 2 or more and 4 or less, the plurality of R11 may be the same or different,
When n is 0, the symbols "*1", "*2" and "*3" each independently represent a linear or branched chain having 1 to 4 carbon atoms which may have a hydroxy group. Represents a bond with an alkyl group or a bond with the polymer chain of the urethane resin,
When n is 1, the symbols "*1", "*2", "*3", and "*4" are bonding portions with the polymer chain of the urethane resin,
When n is 2 or more and 4 or less, the symbols "*1", "*2", "*3" and "*4" may each independently have a bond with a hydrogen atom or a hydroxy group. Represents a bonding portion with a linear or branched alkyl group having 1 to 4 carbon atoms, or a bonding portion with a polymer chain of the urethane resin, and when n is 2 or more and 4 or less, multiple "* 4" may be the same or different, and when n is 2 or more and 4 or less, "*1", "*2", "*3", and a plurality of "* At least four selected from 4” are bonding portions with the polymer chain of the urethane resin. ]. 3. The developer carrier according to claim 1, wherein the number of carbon atoms in the straight chain portion is 100 or more and 1500 or less. The developer carrier according to any one of claims 1 to 3, wherein the linking portion of the two adjacent urethane bonds has a structure represented by the following structural formula (2):

[In Structural Formula (2), L1 represents the aliphatic hydrocarbon structure, R21 represents a linking chain linking one urethane bond and L1, and R23 is a link linking the other urethane bond and L1. represents a chain, p and r are each independently 0 or 1, "*1" represents the bonding portion with one urethane bond, and "*2" represents the bonding portion with the other urethane bond. and L1 comprises a structure represented by structural formula (3) below:

In structural formula (3), q represents an integer of 25 or more and 750 or less, R33 represents a hydrogen atom or an alkyl group having 1 or more and 4 or less carbon atoms, and a plurality of R33 may be the same or different. Alternatively, "*3" represents R21 or the bonding portion with one urethane bond, and "*4" represents R23 or the bonding portion with the other urethane bond. ] 5. The developer carrier according to any one of claims 1 to 4, wherein the linear portion has an unsaturated bond. The developer carrier according to any one of claims 1 to 5, wherein the urethane resin has a partial structure derived from a reaction between a compound represented by the following structural formula (4) and a polyisocyanate:

[in the structural formula (4),
R45 represents a linear or branched alkylene group having 2 to 4 carbon atoms, s is an integer of 0 to 4, and when s is 2 to 4, multiple R45 are the same. may be different.
R41, R42, R43 and R44 are each independently selected from the following (a), (b), (c) and (d), and when s is 2 or more and 4 or less, a plurality of R44 may be the same or different, provided that when s=1, all of R41, R42, R43 and R44 are any one selected from (b), (c) and (d) below. Yes, when s = 2 or more and 4 or less, at least four of R41, R42, R43 and the number of R44 of 2 or more and 4 or less are any selected from the following (b), (c) and (d) be:
(a) a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms;
(b) a linear or branched hydroxyalkyl group having 1 to 8 carbon atoms;
(c) a linear or branched aminoalkyl group having 2 to 8 carbon atoms;
(d) a group represented by the following structural formula (5):

In structural formula (5), t is 2 or 3. A plurality of R51 each independently represents a linear or branched alkylene group having 2 or more and 5 or less carbon atoms. ]. A process cartridge detachably attached to a main body of an electrophotographic image forming apparatus, comprising: a developer container containing a developer; and a developer carrying member for carrying the developer. A process cartridge, wherein the body is the developer carrier according to any one of claims 1 to 6. An electrophotographic image forming apparatus comprising an electrophotographic photoreceptor, a charging member arranged to charge the electrophotographic photoreceptor, and a developer carrier for supplying a developer to the electrophotographic photoreceptor, An electrophotographic image forming apparatus, wherein the developer carrier is the developer carrier according to any one of claims 1 to 6.

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